1. Technical Field
The present invention relates to a tab sheet insertion apparatus, an image forming apparatus having tab sheet inserting function, a method executed on the image forming apparatus, and a computer readable recording medium stored with a control program for controlling the image forming apparatus.
2. Description of the Related Art
There exist printing apparatuses such as copying machines and printers that are capable of creating printed products by inserting between pages a tab sheet having a flat rectangular main body and a tab protruding at a specified position on a side of said may body. See Unexamined Publication No. 2005-182757. In such a printing apparatus, it is customary that multiple sets of tab sheets consisting  of five tab sheets, whose tab positions are sequentially offset from each other, are used as constituents and are placed in a sheet supply tray.
Incidentally, if a printed matter consists of “chapters” and “sections,” it is desirable from the viewpoint of easy and quick browsing of the printed matter to be able to differentiate the tab sheet to be used at the breakpoints of “chapters” from the tab sheet to be used at the breakpoints of “sections.”
However, in the printing apparatus disclosed in the abovementioned patent document, the tab sheets of the same type are supplied from the same sheet supply tray. In other words, tab sheets as constituents with sequentially offset tab positions are supplied and inserted into the printed matter in the sequential order of their stacking in the sheet supply tray. As a result, there was a problem that it is impossible to use tab sheets by dividing them into tab sheets for major divisions and tab sheets for minor divisions, such as tab sheets used at breakpoints of “chapters” and tab sheets used at breakpoints of “sections.”